Datasheet

ManualsBrandsLinear Technology ManualsClockPulse Width Modulator TSOT-23-6

LTC6992-1/LTC6992-2/

LTC6992-3/LTC6992-4

69921234fc

Typical applicaTion

DescripTion

TimerBlox:

Voltage-Controlled Pulse

Width Modulator (PWM)

The LTC

6992 is a silicon oscillator with an easy-to-use

analog voltage-controlled pulse width modulation (PWM)

capability. The LTC6992 is part of the TimerBlox

family

of versatile silicon timing devices.

A single resistor, R

SET

, programs the LTC6992’s inter-

nal master oscillator frequency. The output frequency

is determined by this master oscillator and an internal

frequency divider, N

DIV

, programmable to eight settings

from 1 to 16384.

OUT

1MHz

DIV

•

50kΩ

SET

, N

DIV

= 1,4,16 …16384

Applying a voltage between 0V and 1V on the MOD pin

sets the duty cycle.

The four versions differ in their minimum/maximum duty

cycle. Note that a minimum duty cycle limit of 0% or

maximum duty cycle limit of 100% allows oscillations to

stop at the extreme duty cycle settings.

DEVICE NAME PWM DUTY CYCLE RANGE

LTC6992-1 0% to 100%

LTC6992-2 5% to 95%

LTC6992-3 0% to 95%

LTC6992-4 5% to 100%

For easy configuration of the LTC6992, download the

TimerBlox Designer tool at www.linear.com/timerblox.

Pulse Width Modulation (PWM) Controlled by

Simple 0V to 1V Analog Input

Four Available Options Define Duty Cycle Limits

– Minimum Duty Cycle at 0% or 5%

– Maximum Duty Cycle at 95% or 100%

Frequency Range: 3.81Hz to 1MHz

Configured with 1 to 3 Resistors

<1.7% Maximum Frequency Error

PWM Duty Cycle Error <3.7% Maximum

Frequency Modulation (VCO) Capability

2.25V to 5.5V Single Supply Operation

115μA Supply Current at 100kHz

500μs Start-Up Time

CMOS Output Driver Sources/Sinks 20mA

–55°C to 125°C Operating Temperature Range

Available in Low Profile (1mm) SOT-23 (ThinSOT™)

and 2mm × 3mm DFN

L, LT, LTC and LTM, Linear Technology, TimerBlox and the Linear logo are registered

trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks

are the property of their respective owners.

FeaTures

applicaTions

PWM Servo Loops

Heater Control

LED Dimming Control

High Vibration, High Acceleration Environments

Portable and Battery-Powered Equipment

6992 TA01a

LTC6992

MOD

GND

SET

OUT

DIV

SET

50k

3.3V

ANALOG PWM

DUTY CYCLE

CONTROL

(0V TO 1V)

0.1µF

1MHz Pulse Width Modulator

MOD

0.5V/DIV

OUT

1V/DIV

2µs/DIV

6992 TA01b

Summary of content (34 pages)

PAGE 1
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 TimerBlox: Voltage-Controlled Pulse Width Modulator (PWM) Description Features n n n n n n n n n n n n n Pulse Width Modulation (PWM) Controlled by Simple 0V to 1V Analog Input Four Available Options Define Duty Cycle Limits – Minimum Duty Cycle at 0% or 5% – Maximum Duty Cycle at 95% or 100% Frequency Range: 3.81Hz to 1MHz Configured with 1 to 3 Resistors <1.7% Maximum Frequency Error PWM Duty Cycle Error < 3.7% Maximum Frequency Modulation (VCO) Capability 2.
PAGE 2
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Absolute Maximum Ratings (Note 1) Supply Voltage (V+) to GND..........…………………….6V Maximum Voltage On Any Pin ..............................(GND – 0.3V) ≤ VPIN ≤ (V+ + 0.3V) Operating Temperature Range (Note 2) LTC6992C.............................................–40°C to 85°C LTC6992I..............................................–40°C to 85°C LTC6992H........................................... –40°C to 125°C LTC6992MP........................................
PAGE 3
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 ORDER INFORMATION Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL LTC6992CDCB-4#TRMPBF LTC6992CDCB-4#TRPBF PART MARKING* LFCR 6-Lead (2mm × 3mm) Plastic DFN SPECIFIED TEMPERATURE RANGE 0°C to 70°C LTC6992IDCB-4#TRMPBF LFCR 6-Lead (2mm × 3mm) Plastic DFN –40°C to 85°C LTC6992IDCB-4#TRPBF LTC6992HDCB-4#TRMPBF LTC6992HDCB-4#TRPBF PACKAGE DESCRIPTION LFCR 6-Lead (2mm × 3mm) Plastic DFN LTC6992CS6-4#TRMPBF LTC6992CS6-4#TRPBF LTFCS 6-Lead Plastic TSOT-23 LT
PAGE 4
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Test conditions are V+ = 2.25V to 5.5V, VMOD = 0V to VSET, DIVCODE = 0 to 15 (NDIV = 1 to 16,384), RSET = 50k to 800k, RLOAD = 5k, CLOAD = 5pF unless otherwise noted.
PAGE 5
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Electrical Characteristics Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC6992C is guaranteed functional over the operating temperature range of –40°C to 85°C. Note 3: The LTC6992C is guaranteed to meet specified performance from 0°C to 70°C.
PAGE 6
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics otherwise noted. Frequency Error vs RSET Frequency Drift vs Supply Voltage GUARANTEED MAX OVER TEMPERATURE 2 0.3 200 0.2 DRIFT (%) 1 ERROR (%) 250 0.4 3 PARTS 0 –1 RSET = 50k 0.1 0 –0.1 –0.2 RSET = 200k –0.3 –2 –0.4 GUARANTEED MIN OVER TEMPERATURE –3 50 100 200 RSET (k) 400 –0.5 800 RSET = 800k REFERENCED TO V+ = 4.5V 2 100 0 0.98 6 4 5 3 SUPPLY VOLTAGE (V) VSET Drift vs Supply 0.8 0.8 1.015 0.
PAGE 7
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics V+ = 3.3V, RSET = 200k, and TA = 25°C, unless otherwise noted. 5 NDIV > 1 Duty Cycle Error vs RSET NDIV > 1 Duty Cycle Error vs RSET 5 2 2 2 1 1 1 VMOD/VSET = 0.8 (87.5%) 4 DIVCODE = 4 3 PARTS 3 0 –1 ERROR (%) VMOD/VSET = 0.
PAGE 8
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics V+ = 3.3V, RSET = 200k, and TA = 25°C, unless otherwise noted. NDIV > 1 Duty Cycle Error vs Temperature NDIV > 1 Duty Cycle Error vs Temperature 97 5 5 4 GUARANTEED MAX VMOD/VSET = 0.8 (87.5%) DIVCODE = 4 2 3 PARTS VMOD/VSET = 0.5 (50%) DIVCODE = 4 2 3 PARTS 3 1 1 ERROR (%) 3 0 –1 –3 –3 –5 –50 100 0 25 50 75 TEMPERATURE (°C) –25 100 0 25 50 75 TEMPERATURE (°C) –25 5 3 3 2 2 1 1 VMOD /VSET = 0.
PAGE 9
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics V+ = 3.3V, RSET = 200k, and TA = 25°C, unless otherwise noted. NDIV > 1 Duty Cycle vs VMOD/ VSET 80 3 3 70 LTC6992-2/ LTC6992-4 60 2 LTC6992-2/ LTC6992-3 2 PART C 1 PART B 0 –1 PART A 1 –1 –2 20 –3 –3 LTC6992-1/ 10 DIVCODE = 11 LTC6992-4 3 PARTS 0 0 0.2 0.4 0.6 VMOD/VSET (V/V) –4 –4 –5 1 0.
PAGE 10
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics V+ = 3.3V, RSET = 200k, and TA = 25°C, unless otherwise noted. 0.5 36 34 0.3 33 0.2 32 0.1 31 30 28 –0.3 27 –0.4 26 0.308 –0.5 0.34 0.356 VMOD/VSET (V/V) 0.388 0.372 0.2 95% CLAMP 5% CLAMP VMOD/VSET = 0.8 VMOD/VSET = 0.2 VMOD/VSET = 0.5 3 4 SUPPLY (V) POWER SUPPLY CURRENT (µA) POWER SUPPLY CURRENT (µA) RSET = 100k, ÷4 150 100 RSET = 800k, ÷1 50 0 0 0.2 0.4 0.
PAGE 11
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Performance Characteristics V+ = 3.3V, RSET = 200k, and TA = 25°C, unless otherwise noted. 150 OUTPUT RESISTANCE (Ω) 50 0 –50 –100 –150 –200 3.0 CLOAD = 5pF 45 100 2.5 40 35 OUTPUT SOURCING CURRENT 30 25 20 OUTPUT SINKING CURRENT 15 10 2.0 tRISE 1.5 tFALL 1.0 0.
PAGE 12
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Pin Functions (DCB/S6) V+ (Pin 1/Pin 5): Supply Voltage (2.25V to 5.5V). This supply should be kept free from noise and ripple. It should be bypassed directly to the GND pin with a 0.1μF capacitor. DIV (Pin 2/Pin 4): Programmable Divider and Polarity Input. The DIV pin voltage (VDIV) is internally converted into a 4-bit result (DIVCODE). VDIV may be generated by a resistor divider between V+ and GND. Use 1% resistors to ensure an accurate result.
PAGE 13
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Block Diagram V+ R1 DIV 4 (S6 Package Pin Numbers Shown) 5 4-BIT A/D CONVERTER POL DIGITAL FILTER R2 OUTPUT POLARITY MASTER OSCILLATOR ISET fOSC = 1MHz • 50kΩ • VSET MCLK PULSE WIDTH MODULATOR PROGRAMMABLE DIVIDER ÷1, 4, 16, 64, 256, 1024, 4096, 16384 DUTY CYCLE = VMOD(LIM) – 0.1•VSET tON 0.
PAGE 14
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Operation The LTC6992 is built around a master oscillator with a 1MHz maximum frequency. The oscillator is controlled by the SET pin current (ISET) and voltage (VSET), with a 1MHz • 50k conversion factor that is accurate to ±0.8% under typical conditions. I 1 fMASTER = = 1MHz • 50k • SET tMASTER VSET A feedback loop maintains VSET at 1V ±30mV, leaving ISET as the primary means of controlling the output frequency.
PAGE 15
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Operation Table 1. DIVCODE Programming DIVCODE POL NDIV RECOMMENDED fOUT R1 (kΩ) R2 (kΩ) VDIV /V+ 0 0 1 62.5kHz to 1MHz Open Short ≤0.03125 ±0.015 1 0 4 15.63kHz to 250kHz 976 102 0.09375 ±0.015 2 0 16 3.906kHz to 62.5kHz 976 182 0.15625 ±0.015 3 0 64 976.6Hz to 15.63kHz 1000 280 0.21875 ±0.015 4 0 256 244.1Hz to 3.906kHz 1000 392 0.28125 ±0.015 5 0 1024 61.04Hz to 976.6Hz 1000 523 0.34375 ±0.015 6 0 4096 15.
PAGE 16
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Operation Pulse Width (Duty Cycle) Modulation Output Polarity (POL Bit) The MOD pin is a high impedance analog input providing direct control of the output duty cycle. The duty cycle is proportional to the voltage applied to the MOD pin, VMOD. VMOD 1 Duty Cycle = D = − 0.8 • VSET 8 The duty cycle equation describes a proportional transfer function, where duty cycle increases as VMOD increases.
PAGE 17
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Operation POL = 1 forces a simple logic inversion, so it changes the duty cycle range of the LTC6992-3 (making it 100% to 5%) and LTC6992-4 (making it 95% to 0%). These transfer functions are detailed in Figure 4. 100 Table 2. Duty Cycle Ranges DUTY CYCLE RANGE vs VMOD = 0V → 1V PART NUMBER POL = 0 POL = 1 LTC6992-1 0% to 100% 100% to 0% LTC6992-2 5% to 95% 95% to 5% LTC6992-3 0% to 95% 100% to 5% LTC6992-4 5% to 100% 95% to 0% 100 VMOD /VSET = 0.
PAGE 18
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Operation Changing DIVCODE After Start-Up Start-Up Time Following start-up, the A/D converter will continue monitoring VDIV for changes. Changes to DIVCODE will be recognized slowly, as the LTC6992 places a priority on eliminating any “wandering” in the DIVCODE. The typical delay depends on the difference between the old and new DIVCODE settings and is proportional to the master oscillator period.
PAGE 19
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Applications Information Basic Operation The simplest and most accurate method to program the LTC6992 is to use a single resistor, RSET, between the SET and GND pins. The design procedure is a four step process. After choosing the proper LTC6992 version and POL bit setting, select the NDIV value and then calculate the value for the RSET resistor.
PAGE 20
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 applications information Step 4: Select RSET Calculate the correct value for RSET using Equation (1b). RSET = 1MHz • 50k = 625k 4 • 20kHz Since 625k is not available as a standard 1% resistor, substitute 619k if a 0.97% frequency shift is acceptable. Otherwise, select a parallel or series pair of resistors such as 309k and 316k to attain a more precise resistance. The completed design is shown in Figure 7.
PAGE 21
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Applications Information ISET Extremes (Master Oscillator Frequency Extremes) Pulse Width Modulation Bandwidth and Settling Time When operating with ISET outside of the recommended 1.25μA to 20μA range, the master oscillator operates outside of the 62.5kHz to 1MHz range in which it is most accurate. The LTC6992 has a wide PWM bandwith, making it suitable for a variety of feedback applications.
PAGE 22
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 applications information Power Supply Current The power supply current varies with frequency, supply voltage and output loading. It can be estimated under any condition using the following equation: If N DIV = 1 (DIVCODE = 0 or 15): IS(TYP) ≈ V + • fOUT • ( 39pF + CLOAD ) + V+ V + • Duty Cycle + + 2.2 •ISET + 85µA 320kΩ RLOAD If N DIV > 1 (DIVCODE = 1 or 14): IS(TYP) ≈ V + • NDIV • fOUT • 27pF + V + • fOUT • ( 28pF + CLOAD )  + V+ V + • Duty Cycle + + 2.
PAGE 23
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 applications information MOD OUT LTC6992 V+ GND SET C1 0.1µF V+ R1 DIV RSET R2 V+ R1 R2 V+ C1 C1 V+ OUT MOD OUT DIV GND GND V+ SET MOD SET DIV R1 RSET RSET DFN PACKAGE R2 TSOT-23 PACKAGE 6992 F14 Figure 14. Supply Bypassing and PCB Layout Typical Applications Constant On-Time Modulator VMOD VIN 0V TO 2V RIN* 11.8k VCTRL RM1 1.05k MOD RM2 9.31k GND RSET 44.2k VSET OUT OUT VCC LTC6992-1 SET V+ C1 0.
PAGE 24
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Digitally Controlled Duty Cycle with Internal VREF Reference Variation Eliminated MOD OUT V+ LTC6992-X 0.1µF V+ + 1/2 LTC6078 GND V+ SET DIV RSET C1 0.1µF R1 R2 6992 TA03 – V+ VCC DIN REF VOUT LTC1659 GND 0.1µF µP CLK CS/LD Programming NDIV Using an 8-Bit DAC ANALOG PWM DUTY CYCLE CONTROL (0V TO 1V) MOD OUT LTC6992-X RSET GND V+ SET DIV 2.25V TO 5.5V C1 0.1µF C2 0.
PAGE 25
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Changing Between Two Frequencies ANALOG PWM DUTY CYCLE CONTROL (0V TO 1V) MOD LTC6992-X V+ GND V+ fMAX ANALOG PWM DUTY CYCLE CONTROL (0V TO 1V) OUT 0.1µF RVCO fMIN SET MOD V+ GND V+ V+ 0.1µF R1 SET DIV RSET OUT LTC6992-X V+ R2 RSET2 R1 DIV RSET1 R2 fMIN ‘HC04 fMAX 2N7002 ‘HC04 6992 TA05 NOTES 1. WHEN THE NMOSFET IS OFF, THE FREQUENCY IS SET BY RSET = RSET1. 2.
PAGE 26
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Motor Speed/Direction Control for Full H-Bridge (Locked Anti-Phase Drive) VS 12V 2.6kHz, 5% TO 95% PWM 5% DC = CLOCKWISE 50% DC = STOPPED 95% DC = COUNTER CLOCKWISE INPUT 0V TO 1V MOD A1 CW CURRENT FLOW MOTOR OUT LTC6992-2 GND V+ V+ R1 1000k SET A2 0.1µF POWER H-BRIDGE HIGH = SWITCH ON DIV R3 300k R2 280k 6992 TA07 Motor Speed/Direction Control for Full H-Bridge (Sign/Magnitude Drive) VS 12V A5 A4 2.
PAGE 27
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Ratiometric Sensor to Pulse Width, Non-Inverting Response R6 9.09k VS R4 90.9k VS = 2.5V TO 5.5V R3 K=1 10k RSENSOR K • VS K=0 R5 10M – + C2 0.22µF 0.1µF C1 0.15µF MOD LT1490 OUT LTC6992-1 OUTPUT DUTY CYCLE = K • 100% V+ GND R1 1000k SET RSET 316k VS 0.1µF DIV 6992 TA09 NDIV = 16 fOUT = 10kHz R2 186k Ratiometric Sensor to Pulse Width, Inverting Response R6 9.09k VS VS = 2.5V TO 5.5V R3 100k K=1 RSENSOR R6 90.
PAGE 28
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Radio Control Servo Pulse Generator R6 9.09k C1 1µF R6 90.9k VS VS = 2.5V TO 5.5V R5 130k – + R6 8.66k SERVO CONTROL POT 10k C2 0.22µF 0.1µF MOD LT1490 OUTPUT 1ms TO 2ms PULSE EVERY 16ms OUT LTC6992-1 GND V+ VS R1 1000k 2ms SET 1ms DIV R2 681k 6992 TA11 RSET 196k 0.1µF NDIV = 4096 fOUT = 62.5Hz, 16ms PERIOD Direct Voltage Controlled PWM Dimming (0 to 15000 Cd/m2 Intensity) R3 90.
PAGE 29
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Wide Range LED Dimming (0 to 85000 Cd/m2 Brightness) R2 7.5k VFAST – + 5V R1 10k LT6004 5V 0.1µF FAST PWM CONTROLS 6000 TO 85000 Cd/m2 BRIGHTNESS – + MOD LT6004 R4 7.5k OUT LTC6992-4 V+ GND R3 10k RDIV1 1M VREF SET RSET1 61.9k 5V C4 0.1µF DIV RDIV2 280k 5–100% NDIV = 64 f = 12.6kHz 3.3V 5V 3.3VIN PVIN LED+ A1 D1 PWM LT3518UF D2 VDIMMING 0V TO 1.
PAGE 30
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 typical applications Isolated PWM (5% to 95%) Controller R14 10k 1kHz SOURCE PWM – + 0.1µF LT1011 R2 100k C1 1µF R15 10k R1 10k MOD R9 ISOLATION 20k BARRIER T1 LTC6992-2 GND • L1 • L2 V+ R16 100k R5 20k R3 1k R4 10k LT1011 R10 100kHz 499k INTERMEDIATE PWM R8 10k R18 100k C4 1µF OUT ISOPWM LTC6992-2 GND V+ ISOV+ R12 1M SET R11 787k C3 1000pF LT1636 MOD C2 0.
PAGE 31
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DCB Package 6-Lead Plastic DFN (2mm × 3mm) (Reference LTC DWG # 05-08-1715 Rev A) 0.70 ±0.05 3.55 ±0.05 1.65 ±0.05 (2 SIDES) 2.15 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 1.35 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP R = 0.05 TYP 2.00 ±0.10 (2 SIDES) 3.00 ±0.10 (2 SIDES) 0.40 ± 0.10 4 6 1.65 ± 0.
PAGE 32
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636 Rev B) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.
PAGE 33
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Revision History REV DATE DESCRIPTION A 01/11 Revised θJA value for TSOT package in the Pin Configuration. B C 07/11 01/12 PAGE NUMBER 2 Added Note 7 for VOH and VOL in the Electrical Characteristics table. 4 Minor edit to the Block Diagram. 12 Minor edit to the equation in the “Duty Cycle Sensitivity to ∆VSET” section. 19 Revised Typical Applications drawings.
PAGE 34
LTC6992-1/LTC6992-2/ LTC6992-3/LTC6992-4 Typical Application PWM Controller for LED Driver L1 6.8µH VIN 8V TO 16V SHDN VIN D1 SW FB R2 124k LT3517 ANALOG PWM DUTY CYCLE CONTROL (0V TO 1V) MOD LTC6992-1 GND PWM OUT 5V V+ 0.1µF SET TGEN C1 2.2µF 1M DIV 102k ISP VREF CTRL ISN SYNC TG VC 681k C4 0.1µF RT 6.04k 2MHz RT C1 0.22µF R1 3.92M 300mA RSENSE 330mΩ C2 4.7µF SS GND C3 0.